White talc body with fine silica sand grog. It is mix of two ball clays, 35% talc, and 15% of a blend of two grades of fine silica sand. Fine, white-firing and excellent for detailed modelling and hand building.

Process Properties

Talc/Ball clay bodies tend to be very plastic and slick and have excellent drying properties (although its dry strength is fairly low). This material has added silica sand to further improve drying (the sand also improves its ability to hold up during throwing). F100 is an excellent throwing clay even for large pieces. It is a little rubbery and can be sticky If soft (i.e. difficult to cut off the hump, peel off boards). The fine sand that can be abrasive against the wheelhead but is not otherwise detectable during throwing.


This body must be dried completely before firing, especially if pieces are thick. Early stages of firing should be slow to allow all water to escape (because this has such a high percentage of ball clay).

Fired bars are the classic cone 04 talc body color, however the texture is not quite smooth, due to the fine aggregate. The color shifts from white-buff to yellow-buff above cone 4. This body does not melt at cone 6 as do some talc bodies, however ware will be brittle if fired to that temperature.

This body has a high porosity at cone 06, fire as high as your glazes will take, cone 04 if possible. If you can fire to cone 03 strength will be improved even further.

Fired bars shown are cone 6, 4, 2, 04, 06 (downward).

Left: F100 fired at cone 6 with G2934 base matte glaze (green stained). Right: Fired to cone 03 with G2931L clear base glossy glaze.


F100 is compatible with many commercial cone 06 glazes after bisque firing to cone 04. However it contains 35% talc and this is somewhat less than what is common for white talc bodies. You should therefore test the glazes you use to be sure they do not craze.

F100 with G2931K clear glaze. Fired at cone 03.

Thermal Expansion

We do not supply a thermal expansion value. The reason is that such numbers often mislead users. First, a body has different thermal expansion characteristics when fired at different temperatures, schedules and atmospheres. Dilatometers are only useful when manufacturers can measure bodies and glazes over time and in the same firing conditions. If a chart is supplied here, please view only as a way to compare one body with another.

Another significant issue is that many customers compare measured thermal expansion numbers with calculated values of glazes in efforts to fits those glazes to a body. This does not work. Calculated values are relative only and have limitations that must be understood. The best way to fit glazes to your clay bodies is by testing, evaluation, adjustment and retesting. For example, if a glaze crazes, adjust its recipe to bring the expansion down (using your account at insight-live), fire a glazed piece and thermal stress it (using an IWCT test, 300F into ice-water). If it still crazes, repeat the process.

If we recommend a base clear or glossy glaze, try calculating the expansion of that as a rough guide to know whether your glazes will fit.

Physical Properties

 Drying Shrinkage: 4.5-5.0%
 Dry Strength: n/a
 Drying Factor: B110
 Water Content: 20.0-21 (Mar 99)
 Dry Density: 1.95

Sieve Analysis (Tyler mesh):

     +48     (300 microns): 0.0-0.6%
   48-65 (300-210 microns): 0.4-0.8
  65-100 (210-149 microns): 2.5-3.5
 100-150 (149-106 microns): 2.0-3.0
 150-200  (106-75 microns): 5.5-7.5
 200-325   (75-45 microns): 7.0-10.0

Fired Shrinkage:

   Cone 04: 1.0-1.5%
  Cone 2: 2.5-3.5
  Cone 3: 2.5-3.5
  Cone 5: 2.0-3.5

Fired Absorption:

   Cone 04: 14.5-15%
   Cone 2: 10.0-11.0
  Cone 3: 9.0-10.0
 Cone 5: 10.0-11.0

Safety Data Sheet

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Logo Plainsman Clays Ltd.
702 Wood Street, Medicine Hat, Alberta T1A 1E9
Phone: 403-527-8535 FAX:403-527-7508